This project is concerned with detailed analyses of the organization and morphology of the primate visual cortex, Areas 17, 18 19, by means of correlated techniques of electron microscopy, Golgi studies, fluorescence microscopy, autoradiography and experimental degeneration. Particular emphasis is placed on the careful examination and mapping of the neuronal cell bodies and their processes in the different laminae of this cortex, their patterns of synapses and connections, and on distinguishing the number, size, and topographical distribution of axonal terminals present. Information of this sort on the normal striate cortex and on the cortex of animals with stereotaxically placed electrolytic lesions is necessary for an understanding of the role of individual cells in the architecture and functional physiology of the cortex. BIBLIOGRAPHIC REFERENCES: Chan-Palay, V. Serotonin axons of the supra-and subependymal plexus and in the leptomeninges. Their roles in local alterations of cerebrospinal fluid and vasomotor activity. Brain Research 102:103-130, 1976. Chan-Palay, V. Fine structure of labelled axons in the cerebellar cortex and nuclei of rodents and primates after intraventricular infusions with tritiated serotonin. J. Anat. Embryol. 148:235-265, 1976.